Virus

A new study finds that viruses share some genes exclusively with cells that are not their hosts. The study, reported in the journal Frontiers in Microbiology, adds to the evidence that viruses swap genes with a variety of cellular organisms and are agents of diversity, researchers say.

The study looked at protein structures in viruses and across all superkingdoms, or domains, of life: from the single-celled microbes known as bacteria and archaea, to eukaryotes, a group that includes animals, plants, fungi and all other living things.

A new analysis supports the hypothesis that viruses are living entities that share a long evolutionary history with cells, researchers report. The study offers the first reliable method for tracing viral evolution back to a time when neither viruses nor cells existed in the forms recognized today, the researchers say.

The switchgrass exhibited mosaic symptoms—splotchy, discolored leaves—characteristic of a viral infection, yet tested negative for known infections. Deep sequencing, a new technology, revealed the plants were infected with a new virus in the genus mastrevirus, the first of its kind found in North America.

The microbes could surrender to the harmless virus, but instead freeze in place, dormant, waiting for their potential predator to go away, according to a recent study in mBio.

University of Illinois researchers found that Sulfolobus islandicus can go dormant, ceasing to grow and reproduce, in order to protect themselves from infection by Sulfolobus spindle-shaped virus 9 (SSV9). The dormant microbes are able to recover if the virus goes away within 24 to 48 hours—otherwise they die.